Mechanical Gel Surgical Access Device

ABSTRACT

A mechanical cap ring/gel pad assembly useful in surgical access devices and methods for making the same, wherein the cap ring and the gel pad are formed separately and then mechanically attached to form a strong seal without the need for heating, solvents or adhesives.

BACKGROUND

1. Technical Field

This application is generally directed to a gel surgical access deviceuseful in minimally invasive surgical procedures, and, moreparticularly, to improved methods of manufacturing such devices.

2. Description of the Related Art

Surgical devices incorporating gel pads have been described in the art.For example, hand access devices incorporating gel pads and methods formaking the same are described in U.S. Pat. No. 7,736,306, U.S. Pat. No.7,878,974 and U.S. Pat. No. 7,749,415, the contents of which are herebyincorporated by reference as if set forth in full herein. These describea device in which a cap containing a gel pad may be attached to a woundretractor, to provide sealable hand access into a body cavity whilemaintaining pneumoperitoneum. A natural orifice surgery system has alsobeen described in U.S. Publ. No. 2012/0095297, the contents of which ishereby incorporated by reference as if set forth in full herein. In thispublication, a device is described in which a cap containing a gel padmay be attached to an access device disposed within a natural bodyorifice.

These gel caps generally incorporate gel pads enclosed within a capring, which may be attached to a retractor or other access device duringthe surgical procedure. These cap rings are often formed from apolycarbonate or other plastic materials. During use, pressure is placeon the gel pad as trocars, hands, or other instruments are passedthrough the gel. It may also be important to maintain pneumoperitoneumduring instrument/hand exchange. Accordingly, it is important for thegel pad and the cap ring to form a secure bond and seal.

Current manufacturing practices usually cast the gel pad with the capring to form the bond between them. The gel casting process is done inan oven at elevated temperatures. However, due to the presence of thepolycarbonate cap ring, oven temperatures must be kept lower, and theassembly heated longer, than would be necessary if the gel was cookedalone. Moreover, the polycarbonate rings require complex molds andbraces to prevent deformation during the cooking process and theresulting bond between gel pad and cap ring can vary between lots. Inaddition, the elevated temperatures in the oven may be detrimental tothe mechanical properties of the polycarbonate ring. Finally, oil in thegel material extrudes onto the cap ring during cooking, and significantcleaning must be performed once the gel pad/cap ring assembly is removedfrom the oven.

Some of these problems can be solved by preparing the gel pad separatelyfrom the cap ring. For example, the gel pad can be molded and thenattached to the cap ring with an adhesive, such as cyanoacrylateadhesives, or using solvent welding. Alternatively, the gel pad can becast slightly larger than the cap ring, then compression molded into thering and heated to bond. All of these techniques involve additionallabor steps, the addition of adhesives or solvents, and/or at least someheating of the cap ring with the gel pad, which will then necessitatesignificant cleaning of the assembly.

What is needed, therefore, is a gel pad/cap ring assembly wherein thetwo components are formed separately and then mechanically attached toform a strong seal without the need for heating, solvents or adhesives.With such a manufacturing process, the gel pad can be cooked atsignificantly higher temperatures and for shorter periods of time,enabling rapid manufacturing methods such as injection molding. Theplastic cap rings would no longer be subjected to elevated oventemperatures, eliminating the risk of deformation, and no cleaning toremove oil would be required. The mechanical closure mechanism attachinggel pad to cap ring would serve as bond and seal, no longer varyingbetween lots, and simplified cooking molds for the gel pad could beused, eliminating the need to brace the polycarbonate ring within themold.

SUMMARY OF THE INVENTION

The invention is directed to surgical device having a mechanical gelpad/cap ring assembly, and to methods for manufacturing the same.

In one embodiment, the invention is directed to a method of making a gelcap, comprising providing a split cap ring having a first end and asecond end, the cap ring defining a channel on its inner surface, thefirst end having a pin, and the second end having a boss complementaryto the pin, providing a gel pad sized and configured to fit within thesplit ring cap, disposing the split cap ring around the gel pad, andinserting the pin into the boss to seal the gel pad within the split capring.

In another embodiment, the invention is directed to a method of making agel cap, comprising providing a double split cap ring having a firstend, a second end, a third end and a fourth end, the cap ring defining achannel on its inner surface, the first and third ends each having apin, and the second and fourth ends each having a boss complementary tothe pin, providing a gel pad sized and configured to fit within thedouble split ring cap, disposing the split cap ring around the gel pad,and inserting the pin of the first end into the boss of the second endand the pin of the third end into the boss of the fourth end to seal thegel pad within the double split cap ring.

In another embodiment, the invention is directed to a method of making agel cap, comprising providing a horizontally split cap ring having aproximal piece and a distal piece, the cap ring defining a channel onits inner surface, the proximal piece having at least one boss and atleast one pin on its distal side, the distal piece having at least oneboss and at least one pin on its proximal side, providing a gel padsized and configured to fit within the horizontally split cap ring,placing the gel pad on the proximal surface of the distal cap ringpiece, placing the proximal cap ring piece on the gel pad such that thepin is aligned with the boss on the distal piece and the boss is alignedwith the pin on the distal piece, and inserting the pin into the boss toseal the gel pad within the horizontally split cap ring. In anotherembodiment, the cap ring may have a compression bump disposed on theinner surface of the channel.

In other embodiments, the invention is directed to a method of making agel cap according to any of the previous methods, further comprisingproviding a circular ring disposed within the gel pad around theperiphery of the gel pad.

In other embodiments, the invention is directed to a gel cap made by anyof the processes described herein.

These and other features and advantages of the invention will becomemore apparent with a discussion of embodiments in reference to theassociated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of an embodiment of a mechanical gelsurgical access device; FIG. 1B is an exploded view of the mechanicalgel surgical access device of FIG. 1A.

FIG. 2A is a perspective cross-sectional view of an embodiment of amechanical gel surgical access device; FIG. 2B is a side view of themechanical gel surgical access device of FIG. 2A; FIG. 2C is an explodedview of the mechanical gel surgical access device of FIG. 2A.

FIG. 3A is an exploded perspective view of an embodiment of a mechanicalgel surgical access device; FIG. 3B is an exploded cross-sectional sideview of the mechanical gel surgical access device of FIG. 3A. FIG. 3C isa perspective cross-sectional view of the mechanical gel surgical accessdevice of FIG. 3A.

FIG. 4A is an exploded cross-sectional side view of another embodimentof a mechanical gel surgical access device, showing a compression bump;FIG. 4B is a cross-sectional side view of the mechanical gel surgicalaccess device of FIG. 4A.

FIG. 5A is an exploded cross-sectional side view of another embodimentof a mechanical gel surgical access device, showing an internal o-ringmolded into the gel pad; FIG. 5B is a cross-sectional side view of themechanical gel surgical access device of FIG. 5A.

FIG. 6 is perspective cross-sectional view of an embodiment of amechanical gel surgical access device having pins and bosses penetratingthe gel pad.

Similar components have similar reference numbers throughout.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

As used herein, mechanical gel surgical access device comprises a “gelcap” that incorporates a gel pad coupled to a cap ring. Preferably, theattachment between the gel pad and the cap ring forms a gas-tight seal.Optionally, the gel cap incorporates other features, such as attachmentmechanisms for retractors and other access devices, as has beendescribed in U.S. Pat. No. 7,736,306, U.S. Pat. No. 7,878,974, U.S. Pat.No. 7,749,415, and U.S. Publ. No. 2012/0095297, the contents of whichare hereby incorporated by reference as if set forth in full herein.

The gel pad may be made from an elastomeric gel, some of which have beendescribed in U.S. Pat. No. 7,473,221, the content of which is alsohereby incorporated by reference as if set forth in full herein.

The gel can be prepared by mixing a triblock copolymer with a solventfor the midblocks. The endblocks are typically thermoplastic materialssuch as styrene and the midblocks are thermoset elastomers such asisoprene or butadiene, e.g., Styrene-Ethylene-Butylene-Styrene (SEBS).In one aspect, the solvent used is mineral oil. Upon heating thismixture or slurry, the midblocks are dissolved into the mineral oil anda network of the insoluble endblocks forms. The resulting network hasenhanced elastomeric properties over the parent copolymer. In oneaspect, the triblock copolymer used is KRATON G1651, which has a styreneto rubber ratio of 33/67. Once formed, the gel is substantiallypermanent and, by the nature of the endblocks, processable asthermoplastic elastomers henceforward. The mixture or slurry has aminimum temperature at which it becomes a gel, i.e., the minimum gellingtemperature (MGT). This temperature, in one aspect, corresponds to theglass transition temperature of the thermoplastic endblock plus a fewdegrees. For example, the MGT for the mixture of KRATON G1651 andmineral oil is about 120° C. When the slurry reaches the MGT and thetransformation to a gel state takes place, the gel becomes moretransparent, thereby providing means for visually confirming when thetransformation of the slurry to the gel state is substantially completeand that the gel may be cooled. In addition to triblocks, there are alsodiblock versions of the materials that may be used where Styrene ispresent at only one end of the formula, for example,Styrene-Ethylene/Butylene (SEB).

For a given mass of slurry to form into a complete gel, the entire massof the slurry is heated to the MGT and remains heated at the MGT forsufficient time for the end blocks to form a matrix of interconnections.The slurry will continue to form into gel at temperatures above the MGTuntil the slurry/gel reaches temperatures at which the components withinthe slurry/gel begin to decompose or oxidize. For example, when theslurry/gel is heated at temperatures above 250° C., the mineral oil inthe slurry/gel will begin to be volatile and oxidize. Oxidizing maycause the gel to turn brown and become oily.

The speed at which a given volume of slurry forms a gel is dependant onthe speed with which the entire mass of slurry reaches the MGT. Also,with the application of temperatures higher than the MGT, this speed isfurther enhanced as the end block networks distribute and form morerapidly.

The various base formulas may also be alloyed with one another toachieve a variety of intermediate properties. For example, KRATON G1701Xis a 70% SEB 30% SEBS mixture with an overall Styrene to rubber ratio of28/72. It can be appreciated that an almost infinite number ofcombinations, alloys, and Styrene to rubber ratios can be formulated,each capable of providing advantages to a particular embodiment of theinvention. These advantages will typically include low durometer, highelongation, and good tear strength.

It is contemplated that the gel material may also include silicone, softurethanes and even harder plastics that might provide the desiredsealing qualities with the addition of a foaming agent. The siliconematerial may be of the types currently used for electronicencapsulation. The harder plastics may include PVC, Isoprene, KRATONneat, and other KRATON/oil mixtures. In the KRATON/oil mixture, oilssuch as vegetable oils, petroleum oils and silicone oils may besubstituted for the mineral oil.

Any of the gel materials contemplated could be modified to achievedifferent properties such as enhanced lubricity, appearance, and woundprotection. Additives may be incorporated directly into the gel orapplied as a surface treatment. Other compounds may be added to the gelto modify its physical properties or to assist in subsequentmodification of the surface by providing bonding sites or a surfacecharge. Additionally, oil based colorants may be added to the slurry tocreate gels of different colors.

In one aspect, the mixture/slurry used with the various embodiments ofthe caps that are described herein are composed of about 90% by weightof mineral oil and about 10% by weight of KRATON G1651. From athermodynamic standpoint, this mixture behaves similar to mineral oil.Mineral oil has a considerable heat capacity and, therefore, at about130° C. it can take 3 or 4 hours to heat a pound of the slurrysufficiently to form a homogeneous gel. Once formed, the gel can becooled as quickly as practical with no apparent deleterious effects onthe gel. This cooling, in one aspect, is accomplished with cold-waterimmersion. In another aspect, the gel may be air-cooled. Those familiarwith the art will recognize that other cooling techniques that are wellknown in the art may be employed and are contemplated as within thescope of the present invention.

Many of the properties of the KRATON/oil mixture will vary withadjustments in the weight ratio of the components. In general, thegreater the percentage of mineral oil the less firm the mixture; thegreater the percentage of KRATON, the more firm the mixture. If theresultant gel is too soft it can lead to excessive tenting or doming ofthe gel cap during surgery when a patient's abdominal cavity isinsufflated. Additionally, if the gel is too soft it might not providean adequate seal. However, the gel should be sufficiently soft to becomfortable for the surgeon while simultaneously providing good sealingboth in the presence of an instrument and in the absence of aninstrument.

If the slurry is permitted to sit for a prolonged period of time, thecopolymer, such as KRATON, and the solvent, such as mineral oil, mayseparate. The slurry may be mixed, such as with high shear blades, tomake the slurry more homogeneous. However, mixing the slurry mayintroduce or add air to the slurry. To remove air from the slurry, theslurry may be degassed. In one aspect, the slurry may be degassed in avacuum, such as within a vacuum chamber. In one aspect, the appliedvacuum may be 0.79 meters (29.9 inches) of mercury, or about 1.0atmosphere. The slurry may be stirred while the slurry is under vacuumto facilitate removal of the air. During degassing within a vacuum, theslurry typically expands, then bubbles, and then reduces in volume. Thevacuum may be discontinued when the bubbling substantially ceases.Degassing the slurry in a vacuum chamber reduces the volume of theslurry by about 10%. Degassing the slurry helps reduce the potential ofthe finished gel to oxidize.

Degassing the slurry tends to make the resultant gel firmer. A degassedslurry composed of about 91.6% by weight of mineral oil and about 8.4%by weight of KRATON G1651, an eleven-to-one ratio, results in a gelhaving about the same firmness as a gel made from a slurry that is notdegassed and that is composed of about 90% by weight of mineral oil andabout 10% by weight of KRATON G1651, a nine-to-one ratio.

Mineral oil is of a lighter density than KRATON and the two componentswill separate after mixing, with the lighter mineral oil rising to thetop of the container. This separation may occur when attempting to formstatic slurry into gel over a period of several hours. The separationcan cause the resulting gel to have a higher concentration of mineraloil at the top and a lower concentration at the bottom, e.g., anon-homogeneous gel. The speed of separation is a function of the depthor head height of the slurry being heated. The mass of slurry combinedwith the head height, the temperature at which the gel sets and thespeed with which the energy can be transferred to the gel, factor intothe determination or result of homogeneous gel versus a non-homogeneousgel.

In an embodiment for manufacturing a gel pad 2, the gel slurry is pouredinto a mold cavity of a casting mold. Embodiments of the mold comprise amaterial with sufficient heat dissipation properties, for example, atleast one of aluminum, copper, and brass. Those skilled in the art willrecognize that other mold materials with lower heat dissipationproperties will produce acceptable parts in some embodiments.Furthermore, some embodiments of the mold comprise active coolingelements, for examples, channels through which coolants are pumped.

The mold cavity is filled with a desired amount of the triblockcopolymer/mineral oil slurry such that the slurry fills the mold to thedesired height. In some embodiments, the slurry is preheated, forexample, to about 52° C. (125° F.), which facilitates a complete fillingof the mold cavity by the slurry, thereby reducing the probability ofvoids in the gel. Preheating the slurry to a temperature below the MGTreduces the viscosity of the slurry and allows the slurry to flow moreeasily. As stated above, some embodiments of the slurry are degassed ina vacuum before casting. In some embodiments, the slurry is alsodegassed after it is filled in the mold cavity to remove any air thatmay have been introduced during the filling of the mold cavity, as wellas to facilitate flow of the slurry into voids in the mold. The mold andslurry are heated, for example, in an oven, until the slurry reaches atemperature of about 120° C. to about 150° C.

When the transformation of the slurry into a gel is complete, forexample, when the temperature of the gel pad reaches about 150° C., thegel pad is cooled, for example, by air-cooling, cold-water immersion, oranother suitable method. At 150° C. the gel pad is soft and easilydistorted. Distortions in the gel pad present during cooling would beset after cooling. Accordingly, in some embodiments, the gel pad iscooled within the mold, thereby reducing the likelihood of distortingthe gel pad. Factors affecting the cooling time include the size andconfiguration of the mold, the quantity of gel, temperature and quantityof cooling medium, the properties of the cooling medium, and the moldmaterial. As an example, the cooling time for a particular gel pad maybe about two (2) hours for air cooling and about fifteen (15) minutesfor water cooling. Whether cooling with air or water, the finalproperties of the gel are substantially the same. The gel pad istypically cooled to about ambient room temperature, but may be cooled toa lower temperature if desired. At about 0° C., the gel hardens, whichis useful, for example, in secondary operations such as when couplingseparately manufactured gel pads and cap rings. The gel pad may beremoved from the mold at any time after the gel has set.

When removed from the mold, the gel pad typically has a tacky surface.Coating the gel pad with a powder, such as cornstarch, substantiallyreduces or eliminates the tackiness of the cured gel pad.

The cap ring in some embodiments comprises a polymer. Examples ofsuitable polymers include, at least one of polyethylene (PE), lowdensity polyethylene (LDPE), high density polyethylene (HDPE), ultrahigh molecular weight polyethylene (UHMWPE), polycarbonate,thermoplastic elastomers (DYNAFLEX®, GLS Corp.; KRATON®, KratonPolymers), polyphenylene oxide (PPO), polystyrene, and the like. Thepolymer component of the cap ring is fabricated by any suitable method,including injection molding, melt casting, blow molding, and the like.

In FIGS. 1A and 1B, a mechanical gel surgical access device 1 accordingto one aspect of the present invention is shown. The device includes agel pad 2 and a cap ring 4. Some embodiments of the cap ring 4 comprisea substantially cylindrical ring comprising a proximal portion, a distalportion, and a longitudinal axis extending from the proximal portion todistal portions. The cap ring 4 may also define a channel 6circumscribed along the interior of the cap ring. In other embodiments,the cap ring 4 has another shape or footprint, for example, oval. Asshown in FIG. 1A, the gel pad 2 is disposed within the interior of thecap ring 4.

The cap ring 4 is formed from a first piece and a second piece, eachpiece having one end with a pin 8 and a second end with a boss 10,adapted to receive the pin and form a tight snap fit. To assemble thegel cap, each piece of the cap ring is placed around the gel pad suchthat the pin 8 on the first piece is snapped into the boss 10 of thesecond piece and pin 8 of the second piece is snapped into boss 10 ofthe first piece, compressing the gel pad and forcing gel into thechannel 6 of the cap ring, mechanically locking the cap ring 4 and thegel pad 2 together.

In FIGS. 2A, 2B and 2C, another mechanical gel surgical access device 1according to one aspect of the present invention is shown. Thisembodiment is similar to that of FIG. 1, except that a circular ring 12is disposed within the gel pad 2, along the periphery of the pad. A gelpad with such a ring may be formed in a variety of ways.

In one embodiment, the gel slurry can be poured into a puck-shaped mold,and an inner ring inserted into the gel slurry to create an undercutonce the gel slurry is cured. After curing, the inner ring is removed,leaving an internal groove around the periphery of the gel pad 2. Thecircular ring 12 is then inserted into the groove and the gel padassembled into the cap ring.

In another embodiment of a method for manufacturing a gel pad with acircular ring, the circular ring 12 is placed into a mold that includesa negative space in the desired shape of the gel pad 2. The circularring 12 is supported on pins to raise it above the bottom of the moldbut still below the top of the mold. Sufficient uncured gel is thenadded to the mold to fill the mold, covering the circular ring. Afterthe gel cures, the pad is removed from the mold with the circular ringencased inside the gel.

In still another embodiment of a method for manufacturing a gel pad witha circular ring, the circular ring 12 is suspended between pin holdersin an injection molding cavity. These pins hold the circular ring inposition while the gel slurry is injected into the cavity. The gel isthen cured using standard injection molding techniques.

Preferably, the circular ring is formed from a metal such as stainlesssteel, although nylon or high temperature plastics may be used as well.If bonding between the circular ring and the gel is desired, thecircular ring may be coated or sleeved with polycarbonate, nylon,KRATON®, polyethylene and the like.

To assemble the a mechanical gel surgical access device 1 of FIG. 2,shown in cross-section, each half of the cap ring is placed around thegel pad 2 and pressed together, preferably with a pin and boss snap fitsuch as described for FIG. 1, compressing the gel pad 2 and forcing thecircular ring 12 and the encasing gel into the channel 6 of the cap ring4, mechanically locking the cap ring 4 and the gel pad 2 together.

In another embodiment of a mechanical gel surgical access device, thecap ring 4 is formed as a single piece, with a C-channel 6 and a singlesplit opening. The cap ring of this embodiment is semi-compliant so thatthe two ends of the ring can be spread apart sufficiently to place thering around the gel pad. The two ends are then connected by snap fits,latches, adhesive, welding or some other method to secure the gel padwithin the cap ring.

FIGS. 3A and 3B illustrate another embodiment of a mechanical gelsurgical access device. In this embodiment, the cap ring is splithorizontally into two circular pieces, a proximal piece 16 and a distalpiece 18. Each of the two pieces 16 and 18 circumscribe a shaped channel14, in this example an L-shaped channel. The proximal piece 16 has pins20 and bosses 22 disposed along its distal side, while the distal piece18 has pins 20 and bosses 22 disposed along its proximal side. Thesepins and bosses are arranged in complementary fashion, such that whenthe two pieces of the cap ring are pressed together, the bosses of onepiece receive the pins of the other piece in a press fit. To assemblethe mechanical surgical access device, the gel pad 2 is sandwichedbetween the proximal and distal pieces of the cap ring 16, 18, with thegel pad filling the channels 14 of both pieces. The gel pad is held inplace by the connection of the pins and bosses. A perspective view of across-section of the assembled cap ring/gel pad of the embodiment ofFIG. 3A is shown in FIG. 3C.

A variation of the embodiment of FIG. 3 is shown in FIGS. 4A and 4B. Inthis embodiment, the cap ring is split horizontally into two circularpieces, a proximal piece 24 and a distal piece 26, each of whichcircumscribes a channel 27 on the interior of the ring. Each piece has aprojection, or compression bump 28, extending radially around the innerportion of the ring. The compression bump 28 of the proximal piece 24extends in the distal direction while the compression bump 28 of thedistal piece 26 extends in the proximal direction. When the two piecesare snap fitted together with their respective pins 20 and bosses 22,the channels 27 of the pieces define a channel 29 with the compressionbumps 28 forming a narrow region in the entrance of the channel Toassemble the mechanical surgical access device, the gel pad 2 issandwiched between the proximal and distal pieces of the cap ring 24,26, with the gel pad filling the channel 29. The gel pad is held inplace by the connection of the pins and bosses in the cap ring and isfurther sealed and secured by the pressure of the compression bumps 28.

A variation of the embodiment of FIG. 4 is shown in FIGS. 5A and 5B. Inthis embodiment, the gel pad 30 is formed with a circular ring 32disposed along the periphery of the gel pad as described above. Whenassembled, as shown in FIG. 5B, the circular ring 32, along with thesurrounding gel, is enclosed in channel 29. Compression bumps 28 furthersecure and seal the gel pad with the cap ring. Preferably, the circularring is formed from a metal such as stainless steel, although nylon orhigh temperature plastics may be used as well. If bonding between thecircular ring and the gel is desired, the circular ring may be coated orsleeved with polycarbonate, nylon, KRATON®, polyethylene and the like.

FIG. 6 illustrates another embodiment of a mechanical gel surgicalaccess device. In this embodiment, shown in cross-section, the gel pad34 is formed with a series of holes on the perimeter of the pad. Theseholes may be formed during casting, by providing posts or pins in themold to displace gel slurry, or may be added after the gel pad is cured.The holes form tunnels through which posts 40 on the interior surfacesof the proximal piece 36 and the distal piece 38 of the cap ring maypass. To assemble the mechanical gel surgical access device, the gel padis disposed onto the distal piece of the cap ring, with the posts 40 ofthe distal piece extending up through a portion of the peripheral holesof the gel pad. The proximal piece of the cap ring is then placed on topof the gel pad, with the posts of the proximal piece extending downthrough the remaining holes of the gel pad. The two pieces of the capring are then secured together, preferably by snap fitting pins andbosses (not shown), with the gel pad securely held between them.

While certain embodiments have been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopethereof as defined by the following claims.

What is claimed is:
 1. A method of making a gel cap, comprising: providing a split cap ring having a first end, a second end, and a means for connecting the first end to the second end, the cap ring defining a channel on its inner surface, providing a gel pad sized and configured to fit within the split cap ring, disposing the split cap ring around the gel pad, and connecting the first end to the second end to thereby secure the gel pad within the cap ring.
 2. The method of claim 1, further comprising providing a circular ring disposed within the gel pad around the periphery of the gel pad.
 3. The method of claim 1, wherein the means for connecting comprises a snap fit.
 4. The method of claim 1, wherein the means for connecting comprises a latch.
 5. The method of claim 1, wherein the means for connecting comprises a boss and a pin.
 6. The method of claim 1, wherein the means for connecting comprises an adhesive.
 7. The method of claim 1, wherein the means for connecting comprises a weld.
 8. A gel cap made by the process of claim
 1. 9. A method of making a gel cap, comprising: providing a cap ring comprising a first piece having a first end and a second end, a second piece having a third end and a fourth end, and means for connecting the first end to the third end and the second end to the fourth end, the cap ring defining a channel on its inner surface, providing a gel pad sized and configured to fit within the cap ring, disposing the cap ring around the gel pad, and connecting the first end to the third end and the second end to the fourth end to thereby seal the gel pad within the cap ring.
 10. The method of claim 9, further comprising providing a circular ring disposed within the gel pad around the periphery of the gel pad.
 11. The method of claim 9, wherein the means for connecting comprises a snap fit.
 12. The method of claim 9, wherein the means for connecting comprises a latch.
 13. The method of claim 9, wherein the means for connecting comprises a boss and a pin.
 14. The method of claim 9, wherein the means for connecting comprises an adhesive.
 15. The method of claim 9, wherein the means for connecting comprises a weld.
 16. A gel cap made by the process of claim
 9. 17. A method of making a gel cap, comprising: providing a horizontally split cap ring having a proximal piece, a distal piece, and means for connecting the proximal piece to the distal piece, the cap ring defining a channel on its inner surface, providing a gel pad sized and configured to fit within the horizontally split cap ring, placing the gel pad between the proximal piece and the distal piece, and connecting the proximal piece to the distal piece to thereby seal the gel pad within the horizontally split cap ring.
 18. The method of claim 17, further comprising providing a compression bump disposed on the inner surface of the channel
 19. The method of claim 17, further comprising providing a circular ring disposed within the gel pad around the periphery of the gel pad.
 20. The method of claim 17, wherein the means for connecting comprises a snap fit.
 21. The method of claim 17, wherein the means for connecting comprises a latch.
 22. The method of claim 17, wherein the means for connecting comprises a boss and a pin.
 23. The method of claim 17, wherein the means for connecting comprises an adhesive.
 24. The method of claim 17, wherein the means for connecting comprises a weld.
 25. A gel cap made by the process of claim
 17. 